This invention relates to a tote box especially adapted for use within an automated storage and retrieval material handling system.
Tote boxes are widely used for material handling applications for carrying raw materials, work in process or finished manufacturing goods. Typically, present day tote boxes are of molded plastic construction. While various tote box configurations are available, present day tote boxes do not lend themselves very well to use in an automated storage and retrieval system. Usually, present day tote boxes have an upper rim which defines the greatest outward lateral extension of the tote box. As a result, abutment of two or more like boxes, as they move along the conveyor of the automated storage and retrieval system, occurs at the rims. Since the rim is at the upper edge of the box, a large moment arm is created upon contact to the boxes making damage to the boxes, or more importantly their contents, more likely.
To conserve on floor space, present day tote boxes are often stacked one on top of another. To facilitate such stacking, the tote box is provided with stacking stops near the bottom so that the stacking stops of an upper tote box rest on the side walls of the lower tote box to enable stacking of the boxes whether or not the lower box has a lid. Even where the lower box carries a lid, the stacking stops on the upper box are nevertheless useful as the stacking stops allow the weight of the upper box to be concentrated at or near the edges of the lid material rather than on the lid center, which can be important when the lid is of a relatively thin material. Stacking stops on present day plastic tote boxes are usually not very strong and tend to break or bend, thus requiring an otherwise undamaged tote box to be discarded.
Another problem associated with present day tote boxes arises when, for example, a stack of unlidded boxes is exposed to the elements during external storage, or to water from an automatic sprinkler system or the like in the event of a fire. Water entering the top tote box increases the weight of the box and might cause the stack of boxes to topple or cause serious damage to the entire framework of an automated system. Draining of at least most of the water is important, not only to minimize damage to the contents of the box but also to reduce the extra weight due to the water. Simply allowing the water to flow from the top box into a lower box does not relieve the problem, and may in fact compound it since several boxes in the stack may then be filled with water.
To enable present day plastic tote boxes to transport very small articles, a divider grid is received within the tote box to create a plurality of small compartments, each accommodating a small article so as to segregate different small items. Conventional divider grid arrangements have not proved fully satisfactory from the standpoint of overall strength and ease of use. Moreover, present day divider grids suffer from the drawback that the divider plates lack rigidity so that the divider grid may not always maintain the proper orientation.